Method and devices for specifying the quality of service in a transmission of data packets

ABSTRACT

A system and method for specifying the quality of service in a transmission of data packets between a service entity and a user equipment is provided. A plurality of service classes relating to the quality of service are preconfigured and a selected service class is selected. A first transmission context, associated with a first set of attributes, is established between a core network node and the user equipment. A second transmission context, associated with a second set of attributes, is established between an access node and the user equipment. The selected service class is specified by a third set of attributes, which is forwarded to the core network node and the access node. The third set of attributes is used to determine the first set of attributes and/or the second set of attributes.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a method for specifying the quality ofservice in a transmission of data packets between a service entity and auser equipment over a mobile network comprising a core network node andan access node which are adapted to control the handling of data packetssent between the service entity and the user equipment. Devices andsoftware programs embodying the invention are also described.

BACKGROUND OF THE INVENTION

In many cases, data packets need to be sent between a mobile userequipment and a service entity. Transmissions can be performed both indownlink and uplink direction. For example, a server may send differentpacket flows for sound and video to the user equipment in a streamingsession. The user equipment may send data to the service entity or mayinitiate a streaming session by control signaling. The service entitycan also be another mobile user equipment. The transmission is performedover a mobile network and the service entity may be either part of themobile network or it is able to exchange data packets with the network.

Customary mobile networks comprise a core network with core networknodes, e.g. a serving general packet radio service support node (SGSN)or a gateway general packet radio service support node (GGSN). The corenetwork nodes allow the exchange of data with external networks such asthe Internet or mobile or fixed networks of other operators.Furthermore, customary mobile networks comprise one or more accessnetworks with access network nodes for controlling the radiotransmission to the user equipment, commonly designated, e.g., as basestation controllers, radio network controllers (RNC), Node B or basetransceiver stations.

Depending on the type of packet traffic, the requirements for thetransmission differ significantly. For example, voice transmissionrequires low delay and jitter while a limited amount of errors can beacceptable. Streaming sessions using packet buffers typically allowhigher delays and jitter and the receiver can generally also correct orhide errors while file transfer can often be performed as best-efforttraffic but normally requires error-free data. In addition, operatorsmay choose to offer different qualities of service (QoS) depending onthe user's subscription, i.e. they may choose to perform userdifferentiation. Accordingly, the provision of a defined quality ofservice is an important concept in the control of data traffic asdescribed for example in technical specification 3GPP 23.107 V 6.3.0. ofthe 3^(rd) Generation Partnership Project “Quality of Service (QoS)concept and architecture”.

The quality of service relating to a data transmission involving nodesof the mobile network and the user equipment is defined in differentcontexts. The user equipment and a core network node negotiate a PDP(Packet Data Protocol) context which specifies parameters for thetransmission of data packets to and from the user equipment. Inaddition, further contexts are set up for different links between theservice entity and the user equipment, e.g. a radio bearer between anaccess node and the user equipment, which specifies the transmissionparameters on the radio link. The parameters of the further contexts arenormally determined according to the PDP context. Packet flows betweenthe service entity and the user equipment are then mapped to thesecontexts and forwarded accordingly.

The different contexts all involve attributes for specifying individualparameters of the traffic. In present mobile networks a plurality ofsuch attributes is defined and they may either indicate binary ornumerical values. Accordingly, a high number of possible combinationsfor the values of such attributes exist. In the negotiation orspecification of the attributes for a context, also the user equipmentcan be involved. Depending on manufacturer, model and software, the userequipment can have different requirements and behavior in thespecification procedure of the context, i.e. the setting of theattributes can also depend on the user equipment. This problem maypartly be overcome by performing a specific configuration for the userequipment according to network operator, user equipment manufacturer andtype. This is, however, inconvenient for the user and solves thisproblem only partly.

The differentiated services concept allows marking in the header of adata packet which quality of service should be used when handling thepacket. A corresponding header field is for example defined in differentversions of the Internet Protocol (IP). However, the marking of the datapackets does not allow to forward quality of service information to allnodes controlling the quality of a data transmission in a mobile networkbecause not all nodes are adapted to evaluate the headers. For exampleif the packet transmission involves packet fragmentation and/orencryption with later reassembly or decryption, the headers are normallynot accessible to nodes handling encrypted packets or packet fragments.

Accordingly, it is a problem to specify the quality of service which thenodes in a mobile network use for the handling of data packets. Inaddition, it is also difficult for operators to specify how theresources controlled by the nodes in a mobile network are shared betweendifferent levels of the quality of service.

SUMMARY

It is an object of the present invention to provide a simple solutionfor specifying the quality of service for the handling of data packetsin a mobile network.

In the proposed method, data packets are transmitted between a serviceentity and a user equipment over a mobile network. The mobile networkcomprises a core network node and an access node which are adapted tocontrol the handling of data packets sent between the service entity andthe user equipment. The data packets may be forwarded by the access nodeand the core network node. In addition or alternatively, furtherentities under control of one of the nodes may handle the data packets,e.g. a scheduler in a Node B which is controlled by an RNC as accessnode.

A plurality of service classes relating to the quality of service ispreconfigured. For example, the operator may choose to use a specifiednumber of preconfigured service classes for transmission in the mobilenetwork and to perform all packet transmissions according to one of thepreconfigured service classes. A selected service class is selected fromsaid plurality of service classes for the transmission. For example theselection can be performed by the service entity in view of the requiredquality of service for a specific packet flow or group of flows.

A first transmission context is established between the core networknode and the user equipment. The first transmission context isassociated with a first set of attributes for defining a first qualityof service for the exchange of the data packets with the user equipmentin the transmission. The selected service class determines the first setof attributes by a first unique mapping function performed in the corenetwork node. Preferably, a plurality of first sets is preconfigured inthe core network node and the mapping function performs a selection fromthe preconfigured sets according to the selected service class.

Furthermore, a second transmission context is established between theaccess node and the user equipment. The second transmission context isassociated with a second set of attributes and defines a second qualityof service for the exchange of the data packets with the user equipmentin the transmission. The selected service class determines the secondset of attributes by a second unique mapping function performed in theaccess node. Preferably, a plurality of second sets is preconfigured inthe access node and the mapping function performs a selection from thepreconfigured sets according to the selected service class.

In this way the selected service class defines the handling of the datapackets on the links controlled by the access node and the core networknode and thus the quality of service for the data packets sent betweenthe service entity and the user equipment on the links to which therespective contexts relate.

Preferably, the first and second qualities of service are identical orcorrespond to each other. It is possible that said first and second setsof attributes are sub-sets of larger sets of attributes which may alsocomprise attributes which are specified in another way, e.g. which arepreconfigured to fixed values. It should also be noted that differentservice classes can, via the mapping function, relate to the same firstor second set of attributes, i.e. the number of service classes may belarger than the number of possible sets of attributes.

The proposed method allows a simple specification of the quality ofservice which the nodes in a mobile network use for the handling of datapackets. Due to the attributes being specified by the service classes,the specifications can easily be forwarded between the nodes in themobile network without major adaptations of existing systems. The methodsimplifies it also for operators to specify how the resources controlledby the nodes in a mobile network are shared between different levels ofservice because the operators can specify the resources based on theservice classes without the necessity to define resources based onattributes. A further advantage of the proposed method is that it can beused in existing mobile communication systems after only minoradaptations in the devices.

In present mobile systems, messages are already existing which forwardsets of attributes for the contexts between nodes. In a preferredembodiment of the invention, the selected service class is specified bya third set of attributes which is forwarded to at least one of the corenetwork node and the access node, preferably to both. The first and/orsecond mapping functions determine then the first set of attributesand/or the second set of attributes from the third set of attributes,i.e. according to the service class. This allows to use existingmessages in mobile communication systems for the forwarding of theservice class information to and between nodes. In other words, theselected service class is encoded as a combination of attribute valuesin the third set. It is neither necessary that all possible combinationsof attribute values relate to a service class nor that all attributes inthe third set are used to determine the coded service class.

Preferably, the number of service classes is small compared to thenumber of possible combinations of values in the third set ofattributes. A small number of service classes allows an easyconfiguration of the quality of service by the operator. On the otherhand, the number of service classes must correspond to the requiredgranularity of service differentiation.

It is advantageous, to define the first and/or second mapping functionby a mapping table. For example, the service class can indicate a row inthe table which contains a set of attributes. The mapping table can bespecified during the configuration of the node. It allows a fast andsimple processing of the service classes by the respective nodes and aneasy configuration.

Preferably, a specification of the selected service class is forwardedfrom the service entity to the core network node because the serviceentity is generally aware of the requirements for the quality of servicein a data transmission. It is, however, possible that the specificationsof the service entity are modified, e.g. in an edge node of the corenetwork, if the operator determines that the selected service classshould be changed according to the user's subscription. The serviceentity can specify the requirements for example by packet marking or byusing a defined flow for the packets. In this case, an edge node of thecore network may determine the selected service class from the markingor the flow and forward the specification of the corresponding serviceclass to the core network node. For example, an operator can define twoservice classes each corresponding to a specific packet marking. Basedon those two specific markings, the edge node can then select a first ofthese service classes for users with premium subscriptions and a secondservice class for all other users.

Apart from the core network node and the access node, the data packetscan also be forwarded by other entities which can affect the quality ofservice for the transmission. For example, scheduling entities ondifferent links may delay the data packets. A scheduling entitycontrolled by the access node, typically in the node B, schedules thetransmission of the data packets on a radio link. In this case, theaccess node preferably controls the scheduling entity according to theselected service class.

In an advantageous embodiment, the first mapping function performed inthe core network node is identical to the second mapping functionperformed in the access node, i.e. the first and second sets ofattributes are identical and the same quality of service is specifiedfor all links. However, the properties of different links may deviatesignificantly from each other and different sets and different mappingfunctions can be more advantageous in this case.

Preferably, a configuration procedure defines at least one item from agroup comprising the plurality of service classes, the first mappingfunction, and the second mapping function, e.g. the contents of amapping table. The procedure can be initiated by an operation supportsystem (OSS) of the mobile network which allows it for the operator of amobile network both to specify and change the corresponding parameters.Configuration procedures can also specify and change resources, whichare attributed to all or selected of the service classes in saidplurality of service classes. In this way, reserved resources formandatory services like emergency calls or system signaling as well asreserved bandwidths for users with premium subscriptions can beattributed.

The invention is also embodied in a control device for a mobile networkwhich is adapted to perform the transmission of data packets between aservice entity and a user equipment and which comprises a core networknode and an access node. The nodes are adapted to control the handlingof data packets sent between the service entity and the user equipment.The control device may be one of these nodes or it may be a furtherdevice in the mobile network. A plurality of service classes relating toa quality of service are preconfigured in the mobile network.

The control device comprises a memory in which a unique mapping functionis stored. The function relates the service classes to attributesdefining the quality of service for the transmission of the datapackets. A processing unit is adapted to determine a selected serviceclass for the transmission from said plurality, for example according toparameters in a set-up message for a transmission context. Theprocessing unit is further adapted to specify a set of attributes fromthe selected service class using the unique mapping function, preferablyusing a set of values for the attributes stored in the memory for therespective service class, i.e. the mapping function can for example bedefined in a mapping table. The processing unit is also adapted toestablish a transmission context with the user equipment. Thetransmission context is associated with the set of attributes whichdefine the quality of service for the exchange of the data packets withthe user equipment in the transmission. A control unit controls theforwarding of the data packets according to said set of attributes.

The control device can, for example, be a serving general packet radioservice support node SGSN, a gateway general packet radio servicesupport node GGSN, an enhanced gateway general packet radio servicesupport node, a radio network controller RNC, a base station controller,a base transceiver station, or a Node B. The control device can beadapted for use in any embodiment of the method as described above.

The invention can also be embodied in a program unit comprising code forperforming those steps of a method described above which relate to asingle device. The program unit according to the invention is forexample stored on a data carrier or loadable into a processing unit of acontrol device, e.g. as a sequence of signals.

The foregoing and other objects, features and advantages of the presentinvention will become more apparent in the following detaileddescription of preferred embodiments as illustrated in the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an architecture for providing a defined quality of servicein a mobile system.

FIG. 2 shows the cooperation of nodes in a mobile system in which theinvention is embodied.

FIG. 3 shows an example of a mapping of service classes.

FIG. 4 shows a flow chart of a method according to the invention.

FIG. 5 shows a device according to the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 illustrates a quality of service concept in 3^(rd) generationmobile systems as specified in technical specification 3GPP 23.107 V6.3.0. of the 3^(rd) Generation Partnership Project. Traffic comprisingdata packets is sent between a service entity (AF) and a user equipmentcomprising a terminal equipment (TE) and a mobile terminal (MT). Theservice entity may be a server which could be located in the operator'snetwork or in an external network but it can be also another userequipment. The object of the concept is to provide a defined quality ofservice (QoS) on the application level using the bearer services of theunderlying levels. Those bearer services are specified by contextscomprising attributes for defining the QoS of the respective bearerservice. As the quality of the end-to-end service on the applicationlayer depends on the specifications of the underlying levels, thecontexts of the bearer services need to be specified with respect to therequired end-to-end quality of service.

The TE/MT local bearer service forwards the data packets within the userequipment. The packets are received or sent over a radio link with theradio access network (RAN1) of the mobile network. The External BearerService is provided by another network which can also be a UMTS(Universal Mobile Telephony System) network, i.e. a network according to3GPP specifications, another mobile network or a fixed network like afixed communication system such as the Internet. The external bearerforwards data packets between the service entity (AF) and a gateway node(CN-GW) of the core network of the mobile network. The present inventionis especially concerned with specifying the quality of service for theUMTS bearer service.

The core network comprises also a core network node (CN1) which controlsthe forwarding of packets between core network and radio access network(RAN1). Gateway node (CN-GW) and core network node (CN1) can be the samenode. The data packet traffic through the mobile network is sent over aRadio Access Bearer Service between mobile terminal (MT) and corenetwork node (CN1) and over a Core Network Bearer Service betweenGateway node (CN-GW) and core network node (CN1). These Services are inturn provided by a Radio Bearer Service on the radio link between userequipment and radio access network (RAN1), a RAN Access Bearer Servicebetween radio access network (RAN1) and core network node (CN1) and aBackbone Bearer Service within the core network. Ultimately, allservices depend on different physical bearer services on the respectivelinks, i.e. typically a plurality of contexts and services relate toindividual links in a transmission. A sufficient quality of service isespecially important on bottleneck links in the transmission which limitthe total quality of service. For mobile networks, the bottleneck linkis typically the wireless link between radio access network and mobileterminal.

FIG. 2 shows an example of a transmission of data packets using theproposed method with involved contexts and nodes. For the transmissionof the data packets, a PDP context is negotiated between the userequipment (UE1) and a core network node, here an SGSN (SGSN1). Thetransmission is later performed between core network node and accessnode or at least controlled by them. The dotted line 11 indicates apossible way on which the packets are forwarded in up-link and down-linkdirection between the user equipment (UE) and the service entity (AF).

The set up of the PDP context can for example be initiated by acorresponding request (RQ1) from the user equipment to the SGSN. It isalso possible that the network (e.g., the GGSN) requests the set up ofthe PDP context, for example by a message to the user equipment whichthen initiates the sending of a request (RQ1) to activate a PDP context.

The PDP context comprises attributes which define the quality of servicefor the packet transmission. The establishment of a radio bearer istypically included in the establishment of a PDP context. For thatpurpose, the SGSN (SGSN1) sends a request (12) for establishment of aradio bearer to an access node, in the example an RNC (RNC1). In thestate of the art, the request comprises those attributes of the PDPcontext which are required to establish the radio bearer in line withthe quality of service negotiated in the PDP context. The transmissionof the data packets on the radio link to the user equipment is forexample performed by a node B (NB) which is controlled by the RNC usingradio resource control signaling (13). It is also possible to integratethe functionality of the node B and the RNC in a single node. The node Bcomprises a scheduling entity (SE1) which distributes the arrivingpackets on the available resources, e.g. on shared or dedicatedchannels. As the handling of the packets by the scheduler is importantfor the quality of service of the transmission, the scheduler must alsobe controlled according to the required quality of service. The SGSNsends also a request (14) to an edge node of the core network, here aGGSN (GGSN1), for the establishment of a core network bearer.

The proposed method defines a fixed number of service classes andassociates a pre-configured quality of service with each service class.A service class can further be associated with a service class type. Forexample a scheduler, e.g. scheduling entity (SE1), may distinguish threetypes of service classes: Signaling (SIG), Guaranteed Bit Rate (GBR),and Best-Effort (BE). The configuration defines service class types andwhich services or service components are associated with which serviceclass type.

The attributes defining the quality of service relating to a particularservice class are also preconfigured. Especially those attributes forthe service class that apply to any user are preferably configured fromthe operation support system (OSS) using configuration messages (SIG).Examples for such attributes are an Operator Defined Scheduling Priority(ODSP) or other attributes for the service class like ‘Committed Rate’and ‘Peak Rate’. Also attributes for the service class on a specificlink, e.g. for the radio bearer on the radio link, are preferablyconfigured from the operation support system. Quality of serviceattributes that are specific to both service class and subscriber likeuplink-GBR, downlink-GBR, and uplink-MBR (minimum bit-rate) can beconfigured by the set-up request for a context, e.g. the ‘RABAssignment’. In this case the establishment request (12) for a contextcomprises both an indication of the service class and attributesrelating to the subscriber. The uplink-MBR is relevant for a BE serviceclass since the radio access network, i.e. the uplink scheduler in theNode-B, performs uplink rate policing. The quality of service attributeuplink-MBR is optional for GBR service classes and might be applied forvariable rate codecs (e.g., AMR) or rate-adaptive services.

The requirements for the quality of service are determined by theservice executed on the application layer, e.g. in an application clientexecuted in the user equipment. For example, a speech call in atelephone has strict delay requirements while a streaming service with apacket buffer may tolerate moderate delays and jitter. Accordingly,either the service entity (AF) or the user equipment (UE1) specifies therequired quality of service, for example by marking of the data packetssent or by selecting a flow for the packets. The operator can thenconfigure service classes which relate to selected packet markings or toflows with selected properties. Examples of services an operator maywish to offer could be Internet Access with low data rate, PremiumInternet Access with high data rate, voice over IP telephony includingEmergency Calls or “weShare” which allows users to share media during anongoing telephone call.

In at least some of the involved nodes, in the above example in the SGSNand the RNC, the handling of data packets is performed based on the flowof which the packets are part. A flow, e.g. an IP flow, is usuallydefined by 5 parameters, i.e. source and destination addresses, sourceand destination port numbers and protocol identification. It is,however, not mandatory to use all parameters in the definition of theflow handling. In IP networks, it is also possible to handle datapackets according to the so-called Differentiated Services Code Point(DSCP), which is carried in the IP header. However, the DSCP is not partof the definition of a flow and many nodes in a mobile communicationsystem are not able to evaluate the respective header fields, e.g.because they handle packets after a fragmentation or encryptionperformed during the transmission.

Therefore, the service class identifies preferably flows or aggregatesof flows that are associated with the same quality of service. Thenumber of service classes defined by an operator corresponds to thegranularity of service differentiation that the operator wishes toachieve. Often, 4 to 8 service classes are suitable to allow both asufficient service differentiation and to allow a simple systemconfiguration. In other cases, a higher number of service classes ismore appropriate to allow a better service differentiation. The packettreatment by different nodes can also be defined differently. Forexample, some nodes, e.g. the GGSN, can be adapted to handle packets foreach service class in a different way. Other nodes may map severalservice classes to the same attributes, i.e. packet treatment, forexample if the quality of service depends mainly on a single parameterlike the scheduling priority.

Different applications may be executed simultaneously in the userequipment (UE1) and these applications may exchange data packets withdifferent service entities. Different service entities may send datapackets with different user equipments as destinations to the same edgenode of the mobile network. Packet filters in the user equipment fordistinguishing data packets related to different applications and in theedge node for distinguishing data packets relating to different serviceentities ensure that the packets are sent to the correct destination.Also packets for the same destination can correspond to differentservice classes and need to be associated by the packet filtersaccordingly.

For example, an application-layer service, provided from the serviceentity (AF), e.g. directly by the operator or via peering with a serviceprovider, can include multiple service components each associated with aparticular flow. An operator's policy may define that each of the flowsshould be associated with a different quality of service. For example,an IMS (IP Multimedia Subsystem) service can comprise a signaling flowof the session initiation/session description protocol (SIP/SDP), a flowfor voice, a flow for video, and a flow for file sharing each associatedwith different quality of service. Alternatively, some or all of theflows may be multiplexed on the same quality of service, for exampleSIP/SDP together with VoIP.

Therefore, a packet filter preferably filters a stream of data packetswith one or potentially multiple flows or service classes of potentiallymultiple applications or service components into separate streams, i.e.,associates packets with a particular service class, or associatespackets with a particular PDP context. A packet filter can be defined bya so-called Traffic Flow Template (TFT) that applies to uplink ordownlink. For the downlink, 3GPP specifications also define a PCC(Policy Charging and Control) filter that can be used instead of adownlink TFT.

The flow between the user equipment and the edge node of the corenetwork, e.g. a GGSN, is mapped and potentially multiplexed togetherwith other flows onto a dedicated logical tunnel. In the non-accessstratum between user equipment and core network, the tunnel isrepresented by a PDP context while in the access stratum between userequipment and radio access network it is represented by a radio bearer(RB). The quality of service for a flow in the tunnel is specified bythe service class that is associated with each PDP context and thecorresponding radio bearer, i.e. there is a one-to-one relationshipbetween the PDP context and the radio bearer. Although a tunnel onlyrelates to a single service class, it can accommodate multiple flowseach having different quality of service requirements if they are notdistinguished by packet filters. For example, the service “InternetAccess” can carry flows from diverse applications such as Skype and FTP(File Transfer Protocol).

Within the tunnel, packet markings do not need to be considered. Bymapping a flow onto a tunnel represented by the pair of PDP context andradio bearer with the associated service class for associating a flowwith quality of service, packet marking between user equipment and GGSNto associate the flow with the quality of service is not required. Thisallows a smooth migration of deployed infrastructure based on existing3GPP specifications. However, packet marking may still be used outsidethe tunnel to signal packet-specific quality of service requirements,for example to the user equipment or an edge node of the core network.Accordingly, between inter-connecting backbones of different operators,or between the GGSN and the service entity, packet classification andmarking functions could be used.

Packet marking is one option to signal to the edge node of the corenetwork which service class shall be used for the data packets. The edgenode can then select the service class accordingly. The edge node canalso perform other quality-related functions, e.g. rate policing oradmission control in order to avoid congestion in the mobile network.

Service differentiation allows that an operator controls thedistribution of network resources among the services provided. Servicedifferentiation is, e.g., achieved by priority-based packet schedulingbetween packets of different service classes. In contrast, userdifferentiation allows to control the allocation of network resources toa specific subscriber. For example, if two users both have subscribed tothe service “Internet Access” one may have subscribed to a “standardoption” with lower bit-rate (e.g. uplink/downlink=200/100 kb/s) whilethe other subscriber may have subscribed to a “premium option” withhigher bit-rate (e.g. uplink/downlink=500/250 kb/s). Userdifferentiation is, e.g., achieved by rate policing per PDP context orradio bearer in uplink and/or downlink. In general, user differentiationcan also be performed by reserving service classes to different usergroups and attributing users to the service classes depending on theirsubscription alternatively to or in consideration of a requested qualityof service.

The proposed method provides an effective but simple solution to performservice differentiation by introduction of a fixed number of serviceclasses each associated with a defined quality of service, i.e. bypre-configuring the quality of service that is associated with eachservice class, e.g. by operator policy, and to control the distributionof network resources among the service classes of the services provided.Preferable embodiments do not require changes to the protocols andattributes defined in current 3GPP specifications. It is thereforepossible to use the existing protocols and attributes to allow anoperator to provide service differentiation based on service classes.The proposed method can also reduce time-to-market for operatordeployment of new services because today a new service with defined bitrate requires a new radio access bearer if the required rate is notstandardized. Using service classes, operators can use reserved serviceclasses to test new services without standardization.

Present 3GPP specifications do not provide service classes so that inview of the number of quality of service attributes and thecorresponding value ranges, the number of service classes that can bedefined is huge. This makes it difficult for an operator to control thedistribution of network resources among the service components of allthe services provided and constitutes an obstacle to providing servicedifferentiation.

Operator control over service differentiation can be performed bynetwork-controlled procedures to control the establishment of tunnels,the assignment of a service class per tunnel, and the multiplexing offlows onto a tunnel in uplink and downlink direction. In the prior art,only user equipment-controlled versions of these procedures arespecified. As described above, there are two mechanisms for an operatorto control the distribution of network resources among the differentservice classes. The operation support system can configure quality ofservice attributes that apply to all users. In addition, the request forsetting up a context can specify attributes that are specific to bothservice class and subscriber, e.g. the ‘RAB Assignment’ to controluplink-GBR, downlink-GBR, and uplink-MBR. In present mobile systems, the‘RAB Assignment’ for a GBR radio access bearer always triggers admissioncontrol and results in session management signaling to the userequipment. This precludes the possibility for the network topre-establish a GBR radio access bearer without reserving resources toreduce setup delays although this is an option to reduce setup delays.It is also not possible to trigger admission control without associatedsession management signaling to the user equipment. These options areenabled by the proposed method. Finally, the invention is alsoapplicable for service control in the service layer (e.g., IMS) andfixed-mobile convergence.

The proposed method is especially appropriate for shared channels on theradio link (e.g. in HSPA and Super3G). Some operators provide eachservice from a separate access packet network. In this case,multiplexing is facilitated in the radio access network of PDP contextswith the same service class but from different access packet networks onthe radio link. However, the use of dedicated channels is also possiblefor the proposed method. Preferably, the radio access network is free todecide whether to realize a radio bearer using a shared or a dedicatedchannel if the required quality of service can be ensured in both ways.It is possible that a user equipment has different contexts of the sameservice class. Preferably, a scheduler in the radio access network thenmaps all flows from the contexts onto a single link layer flow(MAC—medium access control) on the radio link.

In a preferable embodiment, combinations of existing quality of serviceattribute values define the service class represented by a service classidentifier (ID). Since there is no quality of service attribute definingthe service class identifier in present 3GPP specifications,combinations of existing quality of service attribute values implicitlydefine the new quality of service attribute service class identifier. Inother words, quality of service attribute values are re-interpreted asencoding a service class.

This means that individual attribute values for the quality of serviceare not used directly to specify the packet handling but they arereinterpreted as constituting a part of the service class definition.When receiving a request for radio bearer assignment, the access node,e.g. the RNC, initially ignores those quality of service attributes thatdo not define the service class. Thus, arbitrary values for, e.g.,uplink-GBR (guarantied bit-rate), downlink-GBR, and uplink-MBR (minimumbit-rate) can be used in the assignment request if these attributes arenot evaluated. However, if the attributes defining the service classindicate a service class in which also user-specific attributes areconsidered, attributes that do not define the service class areevaluated in addition for specifying the user-specific quality ofservice.

As an example, for a PDP context a service class can be a pointer to thequality of service received by the flows that are multiplexed onto thatPDP context. A set of attributes in accordance with the service class ispreferably preconfigured in the core network node. In the same way, aradio bearer is associated with the service class. Within the radioaccess network, the radio bearer represents a tunnel per user equipmentthat is associated with a corresponding PDP context. A user equipmentmay have multiple tunnels simultaneously, i.e. combinations of PDPcontext and radio bearer.

In an example shown in Table 1, the second column indicates a suitablecoding of the service class. For example, the combination of theattributes “interactive”, “signaling indication=Yes” and “THP=1” isinterpreted to specify service class ID “3”. Consequently, the qualityof service attribute ‘Traffic Handling Priority (THP)’ is notinterpreted as a scheduling priority. Instead, the Operator DefinedScheduling Priority is read from the line of the table corresponding toservice class ID “3” and used to control the packet handling. Likewise,the quality of service attribute ‘Signaling Indication’ is notinterpreted as specified in 3GPP TS 23.107 but is used to define theservice class.

TABLE 1 Example of encoding Service-Class-IDs and associating radioaccess bearers with QoS attributes and a radio bearer realization.Encoding of the Operator Defined HS-DSCH/E-DCH Service- Service-Class-IDType of Scheduling Priority Uplink-GBR RB Realization Class- by existingQoS Flow (ODSP) as assigned and (Association to Service ID attributesClass from OSS) downlink-GBR Uplink-MBR class ID assigned from OSS) 1“conversational” GBR 2 Assigned via Assigned via “RLC/UM” + ‘RAB ‘RAB“optimizations Assignment’ Assignment’ for VoIP” (if (Optional) needed)2 “streaming” GBR 3 Assigned via Assigned via “RLC/AM” + ‘RAB ‘RAB“optimizations Assignment’ Assignment’ for Video” (if (Optional) needed)3 “interactive” + SIG 1 N/A Assigned via “RLC/AM” + “signaling ‘RAB“optimizations indication = Yes” + Assignment’ for SIG” (if “THP = 1”needed) 4 “interactive” + BE 4 N/A Assigned via “RLC/AM” + “signaling‘RAB “no specific indication = No” + Assignment’ optimizations” “THP =1” (mostly TCP/IP) 5 “interactive” + BE 5 N/A Assigned via See Flow“signaling ‘RAB Class 4 indication = No” + Assignment’ “THP = 2” 6“interactive” + BE 6 N/A Assigned via See Flow “signaling ‘RAB Class 4indication = No” + Assignment’ “THP = 3” 7 “background” BE 7 N/AAssigned via See Flow ‘RAB Class 4 Assignment’

The other columns of table 1 specify the parameters of the radio bearerfor the access node for the specific service class. Correspondingly,table 1 consists of two sub-tables, the left columns specifying theencoding of the service classes and the other columns specifying thesetting of the attributes according to the service classes. Table 2shows another example of encoding service classes. Here, a furtherparameter (Allocation/Retention Priority ARP) is used in the definitionof the service class to allow defining a higher number of serviceclasses. A corresponding table defines also the attributes relating toeach service class but is omitted here for simplicity.

TABLE 2 Further example of encoding Service-Class-IDs. Service ClassIdentifier Service Class Encoding 0 Reserved for signaling 1“interactive” + “signaling indication = Yes” + “THP = 1” 2“conversational” + “ARP = 1” 3 “conversational” + “ARP = 2” 4“conversational” + “ARP = 3” 5 “streaming” + “ARP = 1” 6 “streaming” +“ARP = 2” 7 “streaming” + “ARP = 3” 8 “interactive” + “signalingindication = No” + “THP = 1” + “ARP = 1” 9 “interactive” + “signalingindication = No” + “THP = 1” + “ARP = 2” 10 “interactive” + “signalingindication = No” + “THP = 1” + “ARP = 3” 11 “interactive” + “signalingindication = No” + “THP = 2” + “ARP = 1” 12 “interactive” + “signalingindication = No” + “THP = 2” + “ARP = 2” 13 “interactive” + “signalingindication = No” + “THP = 2” + “ARP = 3” 14 “interactive” + “signalingindication = No” + “THP = 3” + “ARP = 1” 15 “interactive” + “signalingindication = No” + “THP = 3” + “ARP = 2” 16 “interactive” + “signalingindication = No” + “THP = 3” + “ARP = 3” 17 “background” + “ARP = 1” 18“background” + “ARP = 2” 19 “background” + “ARP = 3”

FIG. 3 further illustrates the setting of attributes for the quality ofservice in an access node. In a first step of receiving (31), the accessnode receives a set of attributes for setting up a context. The accessnode then determines (32) the service class encoded by the attributesusing a mapping function. More specifically, the service class is apointer to a different set of attributes, which is selected (33) from aplurality of sets (34) specified earlier during a configurationprocedure of the access node. The access node then performs control (35)over the transmission of data packets associated with the contextaccording to the selected set of attributes. If the establishmentrequest for a context comprises both an indication of the service classand attributes relating to the subscriber those attributes relating tothe service class are used to select the set of attributes while theother attributes relating to the user can be used to modify the set,i.e. to perform user differentiation.

Preferably, all entities controlling the handling of packets, e.g. theradio access node, SGSN, GGSN, or a PCRF (Policy and Charging RulesFunction) are adapted to handle service classes. In one option, the PCRF(15) has interfaces to the service entity (AF) and the GGSN (GGSN1).Accordingly, it can signal the attributes encoding the service class andthe GGSN as edge node transparently forwards the encoded service class.Alternatively, the PCRF (15) only signals the numerical value of aservice class ID and the GGSN then maps the ID to the correspondingencoding. The service layer, e.g. the PCRF, defines the mapping betweenthe operator-provided service components to service classes, and themapping of service classes to service class types (e.g. GBR, SIG or BE).Admission control may be limited to flows of service class type GBR.

FIG. 4 shows a method according to the invention. The method specifiesthe quality of service in a transmission of data packets between aservice entity and a user equipment over a mobile network comprising acore network node and an access node which are adapted to control thehandling of data packets sent between the service entity and the userequipment.

In a first step (41), a transmission between a service entity and a userequipment is initiated. In a selection (42), a service class is selectedfor the transmission from a plurality of service classes relating to thequality of service which are preconfigured. After the selection (42),the selected service class is communicated to the core network node. Theestablishment (43) of a first transmission context is initiated betweenthe core network node and the user equipment. The first transmissioncontext is associated with a first set of attributes for defining afirst quality of service for the exchange of the data packets with theuser equipment in the transmission. The first set is determined in amapping operation (44) using a unique mapping function which maps theservice class to the first set of attributes. After completion (45) ofthe establishment procedure, transmission control (46) is performedaccording to the transmission context. In this way, the selected serviceclass defines the handling of the data packets as controlled by the corenetwork node, i.e. the transmission control (46) is performed using thefirst set of attributes which is specified in the mapping operation (44)according to the service class.

A second establishment (47) of a second transmission context between theaccess node and the user equipment is also initiated. Typically, thecore network node triggers the second establishment (47) after the firstestablishment is finished although this order of establishment is notessential. The second transmission context is associated with a secondset of attributes which define the quality of service for the exchangeof the data packets with the user equipment in the transmission ascontrolled by the radio access node. In a further mapping operation(48), the second set of attributes is determined in a unique mappingfunction from the selected service class. After completion (49) of thecontext establishment, the selected service class defines accordinglyalso the handling of the data packets controlled by the access node intransmission control (50).

FIG. 5 shows a device according to the invention, for example a servinggeneral packet radio service support node SGSN, a gateway general packetradio service support node GGSN, an enhanced gateway general packetradio service support node, a radio network controller RNC, a basestation controller, a base transceiver station, or a node B. The devicehas a memory unit (MEM) for storing different sets of serviceattributes. It has also an input/output unit (IO) for receiving andsending data packets and receiving messages specifying a selectedservice class for a bearer. A processing unit (PU) is adapted to performa method as described above. Especially, the processing unit candetermine the selected service class from a received message and set upa corresponding bearer to a further device handling the packets.According to the determined selected service class, the processing unitretrieves a corresponding set of attributes from the memory (MEM) andinitiates a control unit (CU) adapted to handle packets sent in thetunnel according to the attributes. The control unit (CU) then handlesthe packets according to the attributes retrieved from the memory, i.e.according to the selected service class. In a preferable embodiment ofthe invention, the processing unit (PU) determines the selected serviceclass from a set of attributes in the received message. The input/outputunit (IO) also allows exchanging messages with an operation supportsystem (OSS1) for configuring the device, especially to define andupdate the attribute sets in the memory (MEM). The units of the controldevice can be embodied as electronic or optical circuitry or as softwareexecuted in such circuitry.

The above embodiments admirably achieve the objects of the invention.However, it will be appreciated that departures can be made by thoseskilled in the art without departing from the scope of the inventionwhich is limited only by the claims.

1. A method for specifying a quality of service in a transmission of data packets between a service entity and a user equipment over a mobile network comprising a core network node and an access node which are adapted to control the handling of data packets sent between the service entity and the user equipment, the method comprising: pre-configuring a defined number of service classes relating to the quality of service; selecting a service class from said defined number of service classes for the transmission, wherein selecting the selected service class further comprises forwarding a third set of attributes to at least one of the core network node and the access node, wherein the third set of attributes specifies the selected service class, the selected service class determining, by a first unique mapping function performed in the core network node, a first set of attributes, and the selected service class determining, by a second unique mapping function performed in the access node, a second set of attributes; establishing a first transmission context between the core network and the user equipment, wherein the first transmission context is associated with the first set of attributes for defining a first quality of service for an exchange of the data packets with the user equipment in the transmission; and establishing a second transmission context between the access node and the user equipment, wherein the second transmission context is associated with the second set of attributes for defining a second quality of service for the exchange of data packets with the user equipment in the transmission.
 2. The method according to claim 1, wherein the number of service classes is small compared to the number of possible combinations of values in the third set of attributes.
 3. The method according to claim 1, wherein at least one of the first and second mapping functions is defined in a mapping table.
 4. The method according to claim 1, wherein a specification of the selected service class is forwarded from the service entity to the core network node.
 5. The method according to claim 1, wherein a scheduling entity controlled by the access node schedules the transmission of the data packets on a radio bearer, the access node controlling the scheduling entity according to the selected service class.
 6. The method according to claim 1, wherein the first mapping function performed in the core network node is identical to the second mapping function performed in the access node.
 7. The method according to claim 1, wherein a configuration procedure defines at least one item from a group comprising the defined number of service classes, the first mapping function, the second mapping function, and resources, which are attributed to one of the service classes in said defined number of service classes.
 8. The method according to claim 1, wherein establishing the first transmission context is initiated by the user equipment.
 9. The method according to claim 1, wherein the first set of attributes are preconfigured with an operation support system using configuration messages; and the second set of attributes are preconfigured with the operation support system using configuration messages. 